At the NRA convention 2 weeks ago here in Charlotte the Blackhorn rep told me I could use Blackhorn in my mk85 but just keep lowering the charge till the blowback subsided.I only took 8 shots with it and was using 100 gr equiv loads. I never had a problem igniting using cci 209m primers. The blowback would about fry my face using this load. I have not used it again since Knight and the folks on here warned me not to use it. I wonder if lowering to about 80 gr would be safe as the Blackhorn rep said.